diff --git a/SurfBezier.cpp b/SurfBezier.cpp
index ad0991d..383c5f2 100644
--- a/SurfBezier.cpp
+++ b/SurfBezier.cpp
@@ -2351,7 +2351,7 @@ SurfBezier::UnprojectPointFromStm( int nT, const Point3d& ptI, Point3d& ptSP, in
             return false ;
          if ( bThroughEdge != nullptr)
             *bThroughEdge = true ;
-         Point3d ptI2 = ptI + ( ptIPrevOrNext - ptI) * EPS_SMALL ;
+         Point3d ptI2 = ptI + ( ptIPrevOrNext - ptI) * 3 * EPS_SMALL ;
          // ricalcolo il triangolo di appartenenza
          DistPointSurfTm dPtStm( ptI2, *pSurfTm) ;
          dPtStm.GetMinDistTriaIndex( nTriaIndex) ;